I am just absurdly interested in these "pegged" coins of all type, as you can tell from my own threads. I was wondering how you would handle the case when the coins were too plentiful and their prices too low, so I'm glad you described your plan.

I am concerned that destroying coins in high transaction fees would lower interest in the coins, leading to lower prices for existing coins, which would force you to raise transaction fees, which would lower interest in the coins, leading to lower prices, . . . you get the picture. Basically, this could result in a divergence which never recovers.

Another concern I have is that you don't want to drive the price too forcefully, or you will limit the impact of goldcoin traders on real-life markets. As long as the prices converge over the long-term, short-term swings are not much concern, and they present arbitrage opportunities.

You might want to consider combining your feedback system with the one I came up with: charging variable transaction fees. If you have a distributed exchange, you can charge no transaction fee when trading at the external spot price for gold, and an increasing transaction fee the further you trade from that spot price. This continually nudges prices toward the external spot price, and helps you not rely so heavily on destroying coins.